It is worth noting that very recently Borodin and Petrov investigated the fully inhomogeneous stochastic higher spin six vertex model in a quadrant [1]}, and the spectral theory was analysed. Our \(q\) -TAZRP model, together with the above mentioned \(q\) -TASEP and ASEP models, can all be regarded as degenerations of the general higher spin six vertex model.
